Battery pack

Abstract

Provided is a battery pack, which can prevent easy detachment of a welded part between a cap plate and a case due to external impact, thereby enhancing hermeticity and reliability.

What is claimed is: 
     
       1. A battery pack, comprising:
 a bare cell having a cap plate that defines a first surface and a first electrode that extends outward from the first surface of the cap plate and a second electrode; and 
 a protection circuit assembly electrically connected with the bare cell and including a protection circuit board having a first and a second side and a protection circuit and a PTC thermistor extending outward from the second side of the protection circuit board wherein the protection circuit board is mounted between the first and second electrode so as to be positioned above the first surface of the cap plate with the protection circuit and PTC thermistor being positioned between the first and second electrode, 
 wherein the protection circuit board includes a protection circuit module having an encapsulating part formed of a first material, and the encapsulating part of the protection circuit module extends from the second side of the protection circuit board towards the first surface wherein the protection circuit board and the encapsulating part define an encapsulated volume containing the protection circuit, the PTC thermistor, and an empty space that extends at least between the protection circuit and the PTC thermistor wherein the encapsulating part is supported by the first surface of the cap plate of the bare cell between the locations where the protection circuit board is connected to the first and second electrodes such that the contact of the bare cell and the protection circuit module inhibits damage to the bare cell as a result of application of external forces to the bare cell and wherein the protection circuit board is directly connected to and supported so as to be suspended over the cap plate by the electrode and the contact of the protection circuit module to the first surface of the cap plate; and 
 a shock absorbing member formed of a second material different than the first material that is directly positioned on the surface of the cap plate and wherein the encapsulating part is directly in contact with the shock absorber member. 
 
     
     
       2. The battery pack according to  claim 1 , wherein the bare cell includes a case having an opening at one side and a cap assembly sealing the case, the cap assembly includes the cap plate that is coupled to the opening, and edges of the cap plate and the opening are welded to each other. 
     
     
       3. The battery pack according to  claim 2 , wherein the case includes narrow side surfaces facing each other and wide side surfaces facing each other, these side surfaces being laterally connected with each other, and a first surface and a second surface formed by being surrounded by the side surfaces, and a distance between the narrow side surfaces facing each other is larger than a distance between the first and second surfaces. 
     
     
       4. The battery pack according to  claim 1 , wherein the protection circuit board further includes a printed circuit board, an external connection terminal and a connection terminal which are mounted on the printed circuit board, and
 the encapsulating part covers the protection circuit and the PTC thermistor so as to form the protection circuit module. 
 
     
     
       5. The battery pack according to  claim 1 , wherein the encapsulating part is formed of resin. 
     
     
       6. The battery pack according to  claim 1 , wherein the protection circuit module is disposed in a middle part of the protection circuit board. 
     
     
       7. The battery pack according to  claim 2 , wherein the bare cell includes a welded part formed by welding an edge of the cap plate and an edge of the opening of the case, and
 wherein the protection circuit module is disposed on an upper surface of the cap plate that has the edge coupled to the welded part. 
 
     
     
       8. The battery pack according to  claim 7 , wherein the protection circuit module is disposed in a middle part of the cap plate. 
     
     
       9. The battery pack according to  claim 2 , wherein the cap plate includes a terminal through-hole, which is eccentrically disposed with respect to the center of the cap plate. 
     
     
       10. The battery pack according to  claim 9 , wherein the terminal through-hole is spaced from approximately the center ½ to ¾ of the distance between approximately the center and the end of the cap plate in a major axis direction. 
     
     
       11. The battery pack according to  claim 1 , wherein the shock-absorber includes a double-sided adhesive tape. 
     
     
       12. A battery pack, comprising:
 a bare cell including a case accommodating an electrode assembly with a first and second electrode and having an opening at one side and a cap assembly sealing the case; and 
 a protection circuit assembly having a protection circuit board having a first and a second side with a protection circuit and PTC thermistor extending outward from the second side of the protection circuit board the protection circuit assembly being electrically connected with the bare cell, 
 wherein the case includes narrow side surfaces facing each other and wide side surfaces facing each other, these surfaces being laterally connected with each other, and first and second surfaces formed by being surrounded by the side surfaces, 
 wherein the cap assembly is coupled to the opening and includes a cap plate having a terminal through-hole, 
 wherein a distance between the narrow side surfaces facing each other is larger than a distance between the first and second surfaces, 
 wherein the terminal through-hole is eccentrically disposed with respect to the center of the cap plate 
 wherein the protection circuit assembly is physically supported so as to be suspended over the cap plate by the first electrode of the electrode assembly that extends through the terminal through-hole and by the second electrode and wherein the protection circuit module has an encapsulating part formed of a first material that extends outward from the second side of the protection circuit board that is supported by the cap plate between the locations wherein the protection circuit module is connected to the first and the second electrode and 
 wherein a shock absorbing member formed of a second material is directly positioned on the first surface of the cap plate and wherein the protection circuit board and the encapsulating part define an encapsulated volume containing the protection circuit, the PTC thermistor, and an empty space that extends at least between the protection circuit and the PTC thermistor and wherein the encapsulating part is directly in contact with the shock absorbing member. 
 
     
     
       13. The battery pack according to  claim 12 , wherein edges of the cap plate and the opening are welded to each other. 
     
     
       14. The battery pack according to  claim 12 , wherein the terminal through-hole is disposed adjacent to an end of the cap plate in a major axis direction. 
     
     
       15. The battery pack according to  claim 14 , wherein the terminal through-hole is spaced from approximately the center ½ to ¾ of the distance between approximately the center and the end of the cap plate in the major axis direction. 
     
     
       16. The battery pack according to  claim 13 , wherein the protection circuit assembly further includes a lead plate to electrically connect the protection circuit board with the bare cell, and
 the protection circuit board includes a printed circuit board, and an external connection terminal and a connection terminal which are mounted on the printed circuit board, and the encapsulating part covers the protection circuit and the PTC thermistor. 
 
     
     
       17. The battery pack according to  claim 12 , wherein the protection circuit, the PTC thermistor and the encapsulating part are disposed in a middle part of the protection circuit board. 
     
     
       18. The battery pack according to  claim 12 , wherein the encapsulating part is formed of resin. 
     
     
       19. The battery pack according to  claim 16 , wherein the bare cell includes a welded part formed by welding an edge of the cap plate and an edge of the opening of the case, and
 wherein the encapsulating part is disposed on an upper surface of the cap plate that has the edge coupled to the welded part. 
 
     
     
       20. The battery pack according to  claim 19 , wherein the encapsulating part is disposed in the middle part of the cap plate.